Can't import a song from my iPhone to computer...

I have apple products for both computer and phone. When I first got my phone a couple of months ago I downloaded a bunch of songs. I'm not sure if I can completely recall exactly what happened except now when I try to import songs from my iPhone there is only one song that doesn't import. It will be completely downloaded to my phone and I can play it before I connect to the computer. Once the device is connected to the computer that's when things change. The song will show up on iTunes as if it's a currupt file, like this:

I have tried deleting off the computer and phone then redownloading to the phone and again computer and it shows up as this once again. I login to my apple email on the computer, and try to find the song and it says I have purchased the song. It just won't let me download from the store. I have numourous times tried to redownload, sync to the computer, unsync to the computer. Nothing has changed. I've been going through this for months and it's starting to drive me banana's. I don't want to call the online support or bring it in to a nearby apple store because I just don't have the money for that right now. Does anyone know what to do?

Please help me someone!